Improvement in countersinks



MOSES MAGOON PETTES, OF WORCESTER,MASSACHUSETTS.

Letters Patent No, 110,494, dated December 27, 1870.

IMPROVEMENT IN CQUNTERVSINKS.

I The Schedule referred to in these Letters Patent and making part ofthe same.

To all persons to whom thesev presents shall come lhoblade D,by'looscning the set-screw F holding Be it known that I, Mosns MAGooNPn'rrris, o1" ,I it in positioincan be adjusted for bit-Shanks ot'greater XVorcestel', in the county ul' Worcester and State o1'Massachusetts, have invented a certain new and useful improvedGountersink; and that the following' is .a full and exact description ofthe saine, rel'onzirc beiughad to the accompanying drawing.

The present invention consists of a novel-constructed counters-ink,adapted' l'or attachment to and detachment from the shank ol' a boringbit.

Inthe accompanying dralviug my improved Wuutersink is illustrated.

Figure 1 is a `side view of a countersnk attach- Figure 4, a side vieu'of a gimlet with a countery sink applied to its shank.

sink.

B, the stock o f the countersink, with its body, C, tubular in shape,and provided on One side with parallel projecting ear-pieces a a.

D, a knife-blade placed in dovetail grooves b of the ear-pieces a,extending between the two and in a direction at an acute angleto theaxis of the body O toward its lower end E.

This blade, at its lower 'end d, is sharpened, and, by means of aset-screw, F, screwing into the carpieces u, the blade can he firmlyfastened and bound in and between the ear-pieces a.

G, a set-screw inserted in' one side of body C, for

securing the same to and ouer the shank or stein of a 5 bit or otherboring-tool. i

lVitha countersink constrluctel as above described applied to the shankof a bit or other boring-tool, as, for instance, a girnlet, (see iig.'4,) and, by its setscrew, G, fastened in position, and its knife-blade,I), properly adjusted, the bore: produced bythe gilnlet, when it hasreached a depth for the cutting-blade l toact, will be countersunk.-

at pleasure for sharpening its cutting-educ or thc in-4 sertion of a newblade.-

ll, a guard or lip applied by its slot f, over the set;

screw F, to the body C. f This guard H projects beyond the plane of thebody G, and by it the amount ot' countcrsiuk to be produced by thecutting-blade can be regulated or adjusted-that is, made either more-orless in depth.

This guard H is also advantageous as a'nieans of regulating the depth towhich the bit or gmlet can bore.

1u fig. 1thc countersink A is shown as applied to a stem or shank, L,which is to be suitably constructed 1' atone end, I, to he secured in abit-stock, and atthe other is constructed with a head, K.

This head K is generally of a conical shape, but4 l has it sides atg andh partially cnt. away so as to A in the drawing represents my improvedcounteri described, may be applied and arranged at an angle ol'inclination directly` on -a bit-shank through the medium of the stock B.v

Having thus described my improved countersink,

, What I claim, and desire to secure by Letters Pat- Sto., in lieu of`ent, is-

Tbe improved coluntersink A, constructed of body O, having ear-pieces ca, knife-blade D, set-screws F G, and adjustable guard or lip H,substantall y as de scribed and for the purpose set forth.

The above-specitication of my invention signed by me this 2d-day ofJuly,31870.'

. M. M. PETTES.

Witnesses EDWIN W. BROWN, ALBERT W. BnowN.

